Method of manufacturing polishing pad having detection window and polishing pad having detection window

ABSTRACT

A polishing pad having a detection window and a method of manufacturing the polishing pad are provided. A dummy detection window is pre-disposed in a mold. A polishing layer precursor is filled into the mold, and then a solidifying process is performed to form a polishing layer, wherein the polishing layer and the dummy detection window are separable completely. The polishing layer and the dummy detection window are separated from each other so as to form a detection opening in the polishing layer. The detection opening can alternatively be formed in a mold having a protrusion structure to replace the dummy detection window. A detection window precursor is filled into the detection opening, and then a solidifying process is performed to form a detection window.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention generally relates to a polishing pad and a method ofmanufacturing the same, and more particularly to a polishing pad havinga detection window and a method of manufacturing the same.

2. Description of Related Art

Along with advancement of the industries, planarization processes areoften adopted as processes for manufacturing various devices. Inplanarization processes, polishing process is often used in theindustries.

Generally, polishing process applies a pressure on an article to bepolished so as to press the article onto a polishing pad, and provides arelative movement between the article and the polishing pad. Throughmechanical friction generated by the relative movement, a portion of asurface layer on the article is removed, so that the surface isgradually planarized, thereby achieving the purpose of planarization.Optionally, polishing solution or polishing slurry containing chemicalcomposition can be applied on the polishing pad during polishingprocess, such that the surface of the article is planarized under thesynergy of mechanical effect and chemical effect.

For a polishing apparatus with an optical detection system, atransparent detection window is usually disposed on a region of thepolishing pad. By detecting the polishing condition on the surface ofthe article through the transparent detection window with the opticaldetection system, user can determine an end-point detection of thepolishing process.

In a conventional method of manufacturing a detection window on apolishing pad, a polishing pad is first manufactured and a detectionopening is formed on the polishing pad by mechanical cutting.Thereafter, a detection window material is filled into the detectionopening and a curing process is carried out for curing the detectionwindow material to form a detection window. However, in this method, thedetection opening is formed on the polishing pad by mechanical cutting,such that an additional cutting procedure is required and the timerequired for manufacturing the polishing pad is increased. As thismethod requires additional mechanical cutting tool, the manufacturingcost may also be higher.

In another conventional method of manufacturing a detection window on apolishing pad, the detection window is first formed and placed in amold. Then, a polishing pad material is filled into the mold and then acuring process is performed, so that the polishing pad having thedetection window is formed. Nevertheless, the bonding strength betweenthe polishing pad and the detection window formed by this method isinsufficient. In other words, using the polishing pad formed by theaforementioned method applying to a longer polishing time accumulated,liquid tends to penetrate through a boundary between the polishing padand the detection window to the optical detection system. Consequently,the end-point detection of the polishing is interfered so as to affectthe polishing quality of the article.

SUMMARY OF THE INVENTION

The invention is directed to a method of manufacturing a polishing padhaving a detection window, where a mechanical cutting procedure is notrequired to form a detection opening.

The invention is directed to a polishing pad having a detection window,in which the detection window and the polishing pad have better bondingstrength therebetween.

The invention is directed to a method of manufacturing a polishing padhaving a detection window. A dummy detection window is pre-disposed in amold. A polishing layer precursor is filled into the mold and asolidifying process is performed to form a polishing layer, wherein thedummy detection window and the polishing layer are separable completely.The dummy detection window and the polishing layer are separated to forma detection opening in the polishing layer. A detection window precursoris filled into the detection opening and a solidifying process isperformed to form a detection window.

The invention is further directed to another method of manufacturing apolishing pad having a detection window. A mold having a protrusionstructure is provided. A polishing layer precursor is filled into themold and a solidifying process is performed to form a polishing layer,in which the protrusion structure defines a detection opening in thepolishing layer. A detection window precursor is filled into thedetection opening and a solidifying process is performed to form adetection window.

The invention is further directed to another method of manufacturing apolishing pad having a detection window. A polishing layer having adetection opening pre-formed therein is provided. A detection window isdisposed in the detection opening, where a gap is between a peripheralsurface of the detection window and an inner side surface of thedetection opening. A buffer layer is filled into the gap.

The invention is directed to a polishing pad having a detection window,and the polishing pad includes a polishing layer, a detection window,and a buffer layer. The polishing layer has a detection opening. Thedetection window is disposed in the detection opening, where a gap isbetween a peripheral surface of the detection window and an inner sidesurface of the detection opening, and the gap is filled by the bufferlayer.

The invention is further directed to a polishing pad having a detectionwindow. The polishing pad includes a polishing layer and a detectionwindow disposed in the polishing layer. In particular, the maximumtensile strength of elastic deformation between the detection window andthe polishing layer is greater than 85 kgf/cm².

In light of the foregoing, the method of manufacturing the polishing paddoes not require mechanical cutting tool to manufacture the detectionopening. Thus, comparing with the conventional method, the method of theinvention has the advantage of simpler procedure and/or lowermanufacturing cost. Furthermore, comparing with the conventional method,the polishing pad of the invention has better bonding strength betweenthe polishing layer and the detection window.

In order to make the aforementioned and other features and advantages ofthe invention more comprehensible, embodiments accompanying figures aredescribed in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIGS. 1A˜1D are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention.

FIGS. 2A to 2D are schematic cross-sectional views along a line I-I′ inFIGS. 1A to 1D.

FIGS. 3A˜3D are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention.

FIGS. 4A to 4D are schematic cross-sectional views along a line II-II′in FIGS. 3A to 3D.

FIGS. 5A˜5E are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention.

FIGS. 6A to 6E are schematic cross-sectional views along a line III-III′in FIGS. 5A to 5E.

FIGS. 7A˜7E are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention.

FIGS. 8A to 8E are schematic cross-sectional views along a line IV-IV′in FIGS. 7A to 7E.

FIGS. 9˜10 are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention.

DESCRIPTION OF EMBODIMENTS First Embodiment

FIGS. 1A˜1D are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention. FIGS. 2A to 2D are schematic cross-sectional views alonga line I-I′ in FIGS. 1A to 1D. Referring to FIG. 1A and FIG. 2A, a mold102 is first provided, and the mold 102 has an accommodating space S foraccommodating a material to be filled into the mold. In the presentembodiment, the shape and size of the accommodating space S of the mold102 is related to the shape and size of a polishing pad to besubsequently formed. In order for persons skilled in the art tounderstand the invention clearly, the mold 102 is partially illustratedin following figures. That is, an upper lid structure of the mold 102 isomitted.

A dummy detection window 104 is pre-disposed on a specific location inthe accommodating space S of the mold 102. This specific locationcorresponds to a location of an optical detection system in a polishingapparatus. The shape and size of the dummy detection window 104 areidentical or similar to the shape and size of the detection window to besubsequently formed in the polishing pad. In the present embodiment, thethickness of the dummy detection window 104 and the depth of theaccommodating space S are about the same. The thickness of the dummydetection window 104 can be adjusted to be little thicker than the depthof the accommodating space S as the dummy detection window 104 isslightly compressed when compressed by the upper lid structure of themold 102. However, the thickness of the dummy detection window 104 canalso be thinner than the depth of the accommodating space S. The dummydetection window 104 is fixed on the specific location of the mold 102by compressing or adhering the dummy detection window 104 in theaccommodating space S between the mold 102 and the upper lid structure.Moreover, the dummy detection window 104 may include a magneticmaterial, such that the dummy detection window 104 can be fixed on thespecific location of the mold 102 by magnetic attachment.

Next, referring to FIG. 1B and FIG. 2B, a polishing layer precursor 106is filled into the mold 102. The polishing layer precursor 106 isusually in a liquid state; thus, the accommodating space S in the mold102 can be filled by injecting or pouring. When the polishing layerprecursor 106 is injected or poured, the mold 102 is sealed by the upperlid structure and only a filling inlet is exposed. Since the dummydetection window 104 is pre-disposed in the accommodating space S of themold 102, the polishing layer precursor 106 fills the accommodatingspace S which is not occupied by the dummy detection window 104. Whenthe thickness of the dummy detection window 104 is about the same as orlittle thicker than the depth of the accommodating space S, the injectedpolishing layer precursor 106 encloses the peripheral surface of thedummy detection window 104. When the thickness of the dummy detectionwindow 104 is thinner than the depth of the accommodating space S, theinjected polishing layer precursor 106 not only encloses the peripheralsurface of the dummy detection window 104, but also covers the uppersurface of the dummy detection window 104. After the polishing layerprecursor 106 is filled into the mold 102, a solidifying process (suchas a curing process) is performed so that the polishing layer precursor106 is solidified to form a polishing layer 106. The foregoingsolidifying process is, for example, a polymerization reaction carriedout intrinsically by reactants in the polishing layer precursor 106, ora polymerization reaction of the polishing layer precursor 106 inducedextrinsically by an irradiation process or a heating process.

Particularly, the polishing layer 106 and the dummy detection window 104are separable completely. In other words, a bonding strength between thepolishing layer 106 and the dummy detection window 104 is relativelyweak. For example, a surface energy difference of the dummy detectionwindow 104 and the polishing layer 106 is greater than 10 mN/m. As aconsequence, the polishing layer 106 and the dummy detection window 104can be easily separated by a small exerted force.

In order to make the polishing layer 106 and the dummy detection window104 be separable completely, the respective materials of the polishinglayer 106 and the dummy detection window 104 are specifically adopted inthe present embodiment. For instance, the polishing layer 106 is formedby adopting a polar material and the dummy detection window 104 isformed by adopting a non-polar material or weak polar material. Indetails, a material of the dummy detection window 104 may includefluoropolymer, polysiloxane, high density polyethylene, low densitypolyethylene, or polypropylene.

According to other embodiments, the dummy detection window 104 can alsobe made of decomposable or dissolvable material. The decomposable ordissolvable material may include polyvinyl alcohol, polylactic acid,polyglucose, cyclodextrin, polystyrene, or salt. When the dummydetection window 104 is made of the decomposable or dissolvablematerial, the dummy detection window 104 and the polishing layer 106 canthen be separated by performing a decomposition or dissolving process.

The dummy detection window 104 may be an opaque dummy detection window,having black, red, blue, or other dark colors, for example, such that anobvious color difference shown between the dummy detection window 104and the light-colored mold 102 (i.e. a metallic color close to gray).Accordingly, the accuracy of the alignment is enhanced whenpre-disposing the dummy detection window 104 on the specific location ofthe mold 102. The polishing layer 106 is made of polyester, polyether,polyurethane, polycarbonate, polyacrylate, polybutadiene, epoxy resin,unsaturated polyester, or ethylene-vinyl acetate copolymer, forinstance. According to an embodiment of the invention, the polishinglayer 106 is made of a material in light color, such as white, gray,light yellow, or other light colors. Therefore, the light-coloredpolishing layer 106 and the dark-colored dummy detection window 104 havean obvious color difference, and then the location of the dummydetection window 104 on the polishing layer 106 can be identifiedeasily.

The dummy detection window 104 and the polishing layer 106 are separatedcompletely so as to form a detection opening 108 in the polishing layer106. As shown in FIG. 1C and FIG. 2C, the shape and size of thedetection opening 108 are about the same as those of the dummy detectionwindow 104. When the thickness of the dummy detection window 104 isabout the same as or little thicker than the depth of the accommodatingspace S, the detection opening 108 penetrates from the top surface tothe bottom surface of the polishing layer 106. The detection opening 108is thus a through opening (i.e. a through hole). When the thickness ofthe dummy detection window 104 is thinner than the depth of theaccommodating space S, the detection opening 108 is then formed on thebottom surface of the polishing layer 106, but does not penetrate thetop surface. Accordingly, the detection opening 108 is a blind opening(i.e. a blind hole). Since the bonding strength between the polishinglayer 106 and the dummy detection window 104 is relatively weak, thedummy detection window 104 can be separated from the polishing layer 106completely by lightly exerting a force thereon. When the dummy detectionwindow 104 is made of the decomposable or dissolvable material, thedummy detection window 104 can then be decomposed or dissolved by adecomposition or dissolving process, such that the detection opening 108is formed in the polishing layer 106.

Referring to FIG. 1D and FIG. 2D, a detection window precursor 110 isfilled into the detection opening 108. The detection window precursor110 is usually in a liquid state; thus, the detection opening 108 can befilled by injecting or pouring the detection window precursor 110.Thereafter, a solidifying process (such as a curing process) isperformed so as to solidify the detection window precursor 110 forforming a detection window 110. The foregoing solidifying process is,for example, a polymerization reaction carried out intrinsically byreactants in the detection window precursor 110, or a polymerizationreaction of the detection window precursor 110 induced extrinsically byan irradiation process or a heating process. In the present embodiment,the material of the detection window 110 includes a material enablingthe light used by the optical detection system to have a transmittanceof at least 50%, for example. This light may be a red light with awavelength ranging from 600 nm to 700 nm or a white light with awavelength ranging from 400 nm to 700 nm.

According to an embodiment of the invention, after the solidifyingprocess is performed for solidifying the detection window precursor 110to form the detection window 110, a surface flattening process isperformed to the polishing layer 106. In the so-called surfaceflattening process, the upper surface layer of the polishing layer 106is trimmed by mechanical trimming, so that the upper surface of thepolishing layer 106 has a flat surface. The upper surface layer of thedetection window 110 may also be trimmed in the surface flatteningprocess, so that the upper surface of the detection window 110 exposedhas the same flat surface as the polishing layer 106.

According to other embodiments of the invention, after the solidifyingprocess is performed for solidifying the detection window precursor 110to form the detection window 110, a grooving process is performed toform groove(s) of a specific shape or distribution in the polishinglayer 106 (not shown). In another embodiment, the corresponding patternwith protrusion(s) complementary to predetermined groove(s) can bedesigned within the mold 102 of FIG. 2A. The groove(s) (not shown) canthen be formed in the polishing layer 106 consequently after theprocesses of filling and solidifying the polishing layer precursor 106depicted in FIG. 2B.

In the foregoing embodiment, the detection opening is formed in thepolishing layer by pre-disposing the dummy detection window. However,the invention is not limited thereto, and other methods can be adoptedto replace the dummy detection window in other embodiments. The detaileddescription is given as follows.

FIGS. 3A˜3D are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention. FIGS. 4A to 4D are schematic cross-sectional views alonga line II-II′in FIGS. 3A to 3D. Embodiments in FIGS. 3A to 3D and FIGS.4A to 4D are similar to the embodiments in FIGS. 1A to 1D and FIGS. 2Ato 2D; thus, the same elements are denoted with the same notations andare not repeated hereinafter.

Referring to FIG. 3A and FIG. 4A, a mold 202 having a protrusionstructure 203 and an accommodating space S is provided. The protrusionstructure 203 is disposed within the accommodating space S of the mold202. The accommodating space S is configured to accommodate a materialto be filled into the mold 202. The location of the protrusion structure203 corresponds to the location of the optical detection system of thepolishing apparatus. In the present embodiment, the shape and size ofthe accommodating space S of the mold 202 is corresponding to the shapeand size of a polishing pad to be subsequently formed. In order forpersons skilled in the art to understand the invention clearly, the mold202 is partially illustrated in following figures. That is, an upper lidstructure of the mold 202 is omitted. In addition, the shape and size ofthe protrusion structure 203 are identical or similar to the shape andsize of the detection window to be subsequently formed in the polishingpad. In the present embodiment, the thickness of the protrusionstructure 203 is about the same as the depth of the accommodating spaceS. According to another embodiment, the thickness of the protrusionstructure 203 can also be thinner than the depth of the accommodatingspace S.

Referring to FIG. 3B and FIG. 4B, a polishing layer precursor 106 isfilled into the mold 202. After the polishing layer precursor 106 isfilled into the mold 202, a solidifying process (such as a curingprocess) is performed so that the polishing layer precursor 106 issolidified to form a polishing layer 106.

Since the mold 202 has the protrusion structure 203, the polishing layer106 is merely formed in the accommodating space S not disposed with theprotrusion structure 203. Therefore, after a demolding process isperformed, the protrusion structure 203 defines a detection opening 108in the polishing layer 106 as shown in FIG. 3C and FIG. 4C. Thedetection opening 108 penetrates from the top surface to the bottomsurface of the polishing layer 106, and is therefore a through opening(i.e. a through hole). Moreover, the shape and size of the detectionopening 108 are about the same as those of the protrusion structure 203.In the foregoing example, the thickness of the protrusion structure 203and the depth of the accommodating space S are about the same. However,when the thickness of the protrusion structure 203 is thinner than thedepth of the accommodating space S, the detection opening 108 formed isthen a blind opening (i.e. a blind hole).

Referring to FIG. 3D and FIG. 4D, a detection window precursor 110 isfilled into the detection opening 108. The detection window precursor110 is usually in a liquid state; thus, the detection opening 108 can befilled by injecting or pouring the detection window precursor 110. Asolidifying process (such as a curing process) is performed so as tosolidify the detection window precursor 110 for forming a detectionwindow 110.

Similarly, after the solidifying process is performed for solidifyingthe detection window precursor 110 to form the detection window 110, asurface flattening process is performed to the polishing layer 106. Inthe so-called surface flattening process, the upper surface layer of thepolishing layer 106 is trimmed by mechanical trimming, so that the uppersurface of the polishing layer 106 has a flat surface. The upper surfacelayer of the detection window 110 may also be trimmed in the surfaceflattening process, so that the upper surface of the detection window110 exposed has the same flat surface as the polishing layer 106.

According to other embodiments of the invention, after the solidifyingprocess is performed for solidifying the detection window precursor 110to form the detection window 110, a grooving process is performed toform groove(s) (not shown) of a specific shape or distribution in thepolishing layer 106. In another embodiment, the corresponding patternwith protrusion(s) complementary to predetermined groove(s) can bedesigned within the mold 202 of FIG. 4A. The groove(s) (not shown) canthen be formed in the polishing layer 106 consequently after theprocesses of filling and solidifying the polishing layer precursor 106depicted in FIG. 4B.

The method of forming the polishing layer 106 and the subsequentdetection window 110 in the mold 202, and the materials andcharacteristics of the polishing layer 106 and the detection window 110are identical to those described in the embodiments of FIG. 1A to FIG.2D, and the descriptions thereof are therefore omitted.

In light of the foregoing, since the present embodiment does not requiremechanical cutting tool to manufacture the detection opening, the methodof the present embodiment has the advantage of simpler procedure and/orlower manufacturing cost comparing with the conventional method.

Second Embodiment

FIGS. 5A˜5E are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention. FIGS. 6A to 6E are schematic cross-sectional views alonga line III-III′in FIGS. 5A to 5E. Embodiments in FIGS. 5A to 5C andFIGS. 6A to 6C are similar to the embodiments in FIGS. 1A to 1C andFIGS. 2A to 2C; thus, the same elements are denoted with the samenotations and are not repeated hereinafter. In particular, stepsillustrated in FIGS. 5A to 5C and FIGS. 6A to 6C are identical orsimilar to the steps depicted in FIGS. 1A to 1C and FIGS. 2A to 2C.

Referring to FIG. 5A and FIG. 6A, a mold 102 having an accommodatingspace S is first provided. A dummy detection window 104 is pre-disposedon a specific location in the accommodating space S. This specificlocation corresponds to a location of an optical detection system in apolishing apparatus. Referring to FIG. 5B and FIG. 6B, a polishing layerprecursor 106 is filled into the mold 102. The method of filling thepolishing layer precursor 106 into the mold 102 and the characteristicsof the polishing layer precursor 106 are all similar to thoseillustrated in the foregoing embodiments, and are thus omitted herein.After the polishing layer precursor 106 is filled into the mold 102, asolidifying process (such as a curing process) is performed so that thepolishing layer precursor 106 is solidified to form a polishing layer106. Similarly, the polishing layer 106 and the dummy detection window104 are separable completely. For example, a surface energy differenceof the dummy detection window 104 and the polishing layer 106 is greaterthan 10 mN/m. As a consequence, the polishing layer 106 and the dummydetection window 104 can be easily separated by a small exerted force.

In the present embodiment, the polishing layer 106 is formed by adoptinga polar material and the dummy detection window 104 is formed byadopting a non-polar material or weak polar material. According to otherembodiments, the dummy detection window 104 can also be made ofdecomposable or dissolvable material. The exemplary embodimentsregarding the materials of the dummy detection window 104 and thepolishing layer 106 are described in the First Embodiment, and are notrepeated hereinafter.

As depicted in FIG. 5C and FIG. 6C, the dummy detection window 104 andthe polishing layer 106 are separated completely to form a detectionopening 108 in the polishing layer 106. The formed detection opening 108may penetrate from the top surface to the bottom surface of thepolishing layer 106. The detection opening 108 is thereby a throughopening (i.e. a through hole). Further, the detection opening 108 mayalso be designed to be formed on the bottom surface of the polishinglayer 106. However, the detection opening 108 does not penetrate the topsurface. The detection opening 108 is thus a blind opening (i.e. a blindhole).

Referring to FIG. 5D and FIG. 6D, a detection window 120 is disposed inthe detection opening 108, where a gap G is present between theperipheral surface of the detection window 120 and an inner side surfaceof the detection opening 108. The detection window 120 is a detectionwindow in a solid state. According to an embodiment of the invention,the material of the detection window 120 includes a material enablingthe light used by the optical detection system to have a transmittanceof at least 50%, for example. This light may be a red light with awavelength ranging from 600 nm to 700 nm or a white light with awavelength ranging from 400 nm to 700 nm.

Referring to FIG. 5E and FIG. 6E, a liquid state buffer layer 122 isfilled into the gap G between the peripheral surface of the detectionwindow 120 and the inner side surface of the detection opening 108.Since the buffer layer 122 filled is a liquid state, the gap G can befilled by injecting or pouring the buffer layer 122. A solidifyingprocess (such as a curing process) is performed so as to solidify theliquid state buffer layer 122 for forming a solid state buffer layer122. The foregoing solidifying process is, for example, a polymerizationreaction carried out intrinsically by reactants in the liquid statebuffer layer 122, or a polymerization reaction of the liquid statebuffer layer 122 induced extrinsically by an irradiation process or aheating process. According to an embodiment of the invention, thematerial of the buffer layer 122 includes a material enabling the lightwith a wavelength ranging from 600 nm to 700 nm to have a transmittanceof at least 50%, for example. Furthermore, the buffer layer 122 may alsobe formed by adopting an energy absorbing material. In the presentembodiment, the polishing layer 106 may be formed by adopting anaromatic-rich material, the detection window 120 may be formed byadopting an aliphatic-rich material, and a material of the buffer layer122 ranges therebetween (i.e. the material of the buffer layer 122 hasan aromatic functional group content ranging between the polishing layer106 and the detection window 120).

According to an embodiment of the invention, after the solidifyingprocess is performed for solidifying the liquid state buffer layer 122to form a solid state buffer layer 122, a surface flattening process isperformed to the polishing layer 106. In the so-called surfaceflattening process, the upper surface layer of the polishing layer 106is trimmed by mechanical trimming, so that the upper surface of thepolishing layer 106 has a flat surface. The upper surface layer of thebuffer layer 122 and the detection window 120 may also be trimmed in thesurface flattening process, so that the upper surface of the bufferlayer 122 and the detection window 120 exposed has the same flat surfaceas the polishing layer 106. According to other embodiments of theinvention, after the solidifying process is performed to the bufferlayer 122, a grooving process is performed to form groove(s) of aspecific shape or distribution in the polishing layer 106 (not shown).In another embodiment, the corresponding pattern with protrusion(s)complementary to predetermined groove(s) can be designed within the mold102 of FIG. 6A. The groove(s) (not shown) can then be formed in thepolishing layer 106 consequently after the processes of filling andsolidifying the polishing layer precursor 106 depicted in FIG. 6B.

In the foregoing embodiment, the detection opening is formed in thepolishing layer by pre-disposing the dummy detection window. However,the invention is not limited thereto, and other methods can be adoptedto replace the dummy detection window in other embodiments. The detaileddescription is given as follows.

FIGS. 7A˜7E are schematic top views of a method of manufacturing apolishing pad having a detection window according to an embodiment ofthe invention. FIGS. 8A to 8E are schematic cross-sectional views alonga line IV-IV′ in FIGS. 7A to 7E. Embodiments in FIGS. 7A to 7C and FIGS.8A to 8C are similar to the embodiments in FIGS. 3A to 3C and FIGS. 4Ato 4C; thus, the same elements are denoted with the same notations andare not described hereinafter. Especially, steps illustrated in FIGS. 7Ato 7C and FIGS. 8A to 8C are identical or similar to the steps depictedin FIGS. 3A to 3C and FIGS. 4A to 4C. Embodiments in FIGS. 7D to 7E andFIGS. 8D to 8E are similar to the embodiments in FIGS. 5D to 5E andFIGS. 6D to 6E; thus, the same elements are denoted with the samenotations and are not described hereinafter. Especially, stepsillustrated in FIGS. 7D to 7E and FIGS. 8D to 8E are identical orsimilar to the steps depicted in FIGS. 5D to 5E and FIGS. 6D to 6E.

Referring to FIG. 7A and FIG. 8A, a mold 202 having a protrusionstructure 203 and an accommodating space S is provided. The location ofthe protrusion structure 203 corresponds to the location of the opticaldetection system of the polishing apparatus. Referring to FIG. 7B andFIG. 8B, a polishing layer precursor 106 is filled into the mold 202.The method of filling the polishing layer precursor 106 into the mold202 and the characteristics of the polishing layer precursor 106 are allsimilar to those illustrated in the foregoing embodiments, and are thusomitted herein. After the polishing layer precursor 106 is filled intothe mold 202, a solidifying process (such as a curing process) isperformed so that the polishing layer precursor 106 is solidified toform a polishing layer 106.

Since the mold 202 has the protrusion structure 203, the polishing layer106 is merely formed in the accommodating space S where the protrusionstructure 203 is not disposed. Therefore, after a demolding process isperformed, the protrusion structure 203 defines a detection opening 108in the polishing layer 106 as shown in FIG. 7C and FIG. 8C. Thedetection opening 108 may penetrate from the top surface to the bottomsurface of the polishing layer 106, and is therefore a through opening(i.e. a through hole). Moreover, the shape and size of the detectionopening 108 are about the same as those of the protrusion structure 203.Moreover, the detection opening 108 formed in the polishing layer 106may also be a blind opening (i.e. a blind hole) through the design ofthe protrusion structure 203.

Referring to FIG. 7D and FIG. 8D, a detection window 120 is disposed inthe detection opening 108, where a gap G is present between theperipheral surface of the detection window 120 and an inner side surfaceof the detection opening 108. The detection window 120 is a detectionwindow in a solid state. According to an embodiment of the invention,the material of the detection window 120 includes a material enablingthe light used by the optical detection system to have a transmittanceof at least 50%, for example. This light may be a red light with awavelength ranging from 600 nm to 700 nm or a white light with awavelength ranging from 400 nm to 700 nm.

Referring to FIG. 7E and FIG. 8E, a liquid state buffer layer 122 isfilled into the gap G between the peripheral surface of the detectionwindow 120 and the inner side surface of the detection opening 108.Since the buffer layer 122 filled is in a liquid state, the gap G can befilled by injecting or pouring the buffer layer 122. A solidifyingprocess (such as a curing process) is performed so as to solidify theliquid state buffer layer 122 for forming the solid state buffer layer122. The foregoing solidifying process is, for example, a polymerizationreaction carried out intrinsically by reactants in the liquid statebuffer layer 122 or a polymerization reaction of the liquid state bufferlayer 122 induced extrinsically by an irradiation process or a heatingprocess. According to an embodiment of the invention, the material ofthe buffer layer 122 includes a material enabling the light with awavelength ranging from 600 nm to 700 nm to have a transmittance of atleast 50%, for example. Furthermore, the buffer layer 122 may also beformed by adopting an energy absorbing material. In the presentembodiment, the polishing layer 106 may be formed by adopting anaromatic-rich material, the detection window 120 may be formed byadopting an aliphatic-rich material, and a material of the buffer layer122 ranges therebetween (i.e. the material of the buffer layer 122 hasan aromatic functional group content ranging between the polishing layer106 and the detection window 120).

According to an embodiment of the invention, after the solidifyingprocess is performed for solidifying the liquid state buffer layer 122to form a solid state buffer layer 122, a surface flattening process isperformed to the polishing layer 106. In the so-called surfaceflattening process, the upper surface layer of the polishing layer 106is trimmed by mechanical trimming, so that the upper surface of thepolishing layer 106 has a flat surface. The upper surface layer of thebuffer layer 122 and the detection window 120 may also be trimmed in thesurface flattening process, so that the upper surface of the bufferlayer 122 and the detection window 120 exposed has the same flat surfaceas the polishing layer 106. According to other embodiments of theinvention, after the solidifying process is performed to the bufferlayer 122, a grooving process is performed to form groove(s) of aspecific shape or distribution in the polishing layer 106 (not shown).In another embodiment, the corresponding pattern with protrusion(s)complementary to predetermined groove(s) can be designed within the mold102 of FIG. 8A. The groove(s)) can then be formed in the polishing layer106 consequently after the processes of filling and solidifying thepolishing layer precursor 106 depicted in FIG. 8B. The polishing padhaving the detection window formed by using the method described in theSecond Embodiment is illustrated in FIG. 5E (FIG. 6E) or FIG. 7E (FIG.8E), and the polishing pad includes a polishing layer 106, a detectionwindow 120, and a buffer layer 122. The polishing layer 106 has adetection opening 108, the detection window 120 is disposed in thedetection opening 108, where a gap G is present between the peripheralsurface of the detection window 120 and an inner side surface of thedetection opening 108. The gap G is filled with the buffer layer 122.According to an embodiment of the invention, the polishing layer 106 isformed by adopting polyester, polyether, polyurethane, polycarbonate,polyacrylate, polybutadiene, epoxy resin, unsaturated polyester, orethylene-vinyl acetate copolymer, for instance. The material of thedetection window 120 includes a material enabling the light used by theoptical detection system to have a transmittance of at least 50%, forexample. This light may be a red light with a wavelength ranging from600 nm to 700 nm or a white light with a wavelength ranging from 400 nmto 700 nm. The material of the buffer layer 122 includes a materialenabling the light with a wavelength ranging from 600 nm to 700 nm tohave a transmittance of at least 50%, for example. Furthermore, thebuffer layer 122 may also be formed by adopting an energy absorbingmaterial. In the present embodiment, the polishing layer 106 may beformed by adopting an aromatic-rich material, the detection window 120may be formed by adopting an aliphatic-rich material, and a material ofthe buffer layer 122 ranges therebetween (i.e. the material of thebuffer layer 122 has an aromatic functional group content rangingbetween the polishing layer 106 and the detection window 120).

It should be noted that in the embodiments of FIG. 5C and FIG. 7C, thedetection opening 108 formed is a through opening having a single size.However, according to other embodiments as illustrated in FIG. 9, thedetection opening 108 formed may also have dual sizes which includes acentral part 108 a and a peripheral part 108 b surrounding the centralpart 108 a. The central part 108 a of the detection opening 108 is apenetrating part and the peripheral part 108 b of the detection opening108 is a non-penetrating part. That is, the bottom of the peripheralpart 108 b includes the partial thickness of the polishing layer 106. Bydesigning the detection opening 108 as that shown in FIG. 9, betteralignment can be attained in the following steps of disposing thedetection window and filling the buffer layer. As depicted in FIG. 10,the detection window 120 is disposed in the central part 108 a of thedetection opening 108. Since the central part 108 a and the peripheralpart 108 b of the detection opening 108 have a height difference, theperipheral part 108 b can be used for aligning when the detection window120 is being disposed. The buffer layer 122 is then filled in theperipheral part 108 b of the detection opening 108.

In summary, since the embodiments aforementioned do not requiremechanical cutting tool to manufacture the detection opening, the methodof the present embodiment has the advantage of simpler procedure and/orlower manufacturing cost comparing with the conventional method.

According to the polishing pad having the detection window formed by themethods illustrated in the First Embodiment and the Second Embodiment,the maximum tensile strength of elastic deformation between thedetection window and the polishing layer is greater than 85 kgf/cm², andranges from 90 kg f/cm² to 100 kgf/cm², for example. The polishing padof the invention has better bonding strength between the detectionwindow and the polishing layer comparing with the conventional method,where a pre-manufactured detection window is disposed in a mold, apolishing layer material is filled into the mold, and a solidifyingprocess is performed to form a polishing pad having the detectionwindow. Table 1 shows a comparison of bonding strength between thedetection window and the polishing layer. Here, the polishing layer isformed by adopting aromatic-rich polyurethane, the detection windowmaterial B is aliphatic-rich polyurethane, and the material A of thedetection window or the buffer layer is polyurethane with an aromaticfunctional group content ranging between the polishing layer and thedetection window material B. In addition, the energy absorbing abilityof the material A of the detection window or the buffer layer is greaterthan that of the detection window material B.

TABLE 1 Maximum tensile strength of elastic deformation Conventionalcomparative embodiment 62 kgf/cm² (detection window material A)Conventional comparative embodiment 84 kgf/cm² (detection windowmaterial B) First Embodiment (detection window 90 kgf/cm² material A)First Embodiment (detection window 95 kgf/cm² material B) SecondEmbodiment (detection window 97 kgf/cm² material B/buffer layer materialA)

In the embodiments of the invention, only one detection window isutilized for illustration. However, a polishing pad having a pluralityof detection windows can also be formed by using the same method.Furthermore, the polishing pad of the invention can be applied forpolishing surfaces of objects in the manufacture of industrial devices.These objects include semiconductor wafers, III-V group wafers, storagedevice carriers, ceramic substrates, polymer substrates, glasssubstrates and so on. Nevertheless, the scope of the invention is notlimited thereto.

Although the invention has been described with reference to the aboveembodiments, it will be apparent to one of the ordinary skill in the artthat modifications to the described embodiment may be made withoutdeparting from the spirit of the invention. Accordingly, the scope ofthe invention will be defined by the attached claims not by the abovedetailed descriptions.

1. A method of manufacturing a polishing pad having a detection window,the method comprising: pre-disposing a dummy detection window in a mold;filling a polishing layer precursor into the mold and performing asolidifying process to form a polishing layer, wherein the dummydetection window and the polishing layer are separable completely;separating the dummy detection window and the polishing layer to form adetection opening in the polishing layer; and filling a detection windowprecursor into the detection opening and performing a solidifyingprocess to form a detection window.
 2. The method of manufacturing thepolishing pad as claimed in claim 1, wherein a surface energy differencebetween the dummy detection window and the polishing layer is greaterthan 10 mN/m.
 3. The method of manufacturing the polishing pad asclaimed in claim 1, wherein a material of the polishing layer is a polarmaterial and a material of the dummy detection window is a non-polarmaterial or a weak polar material.
 4. The method of manufacturing thepolishing pad as claimed in claim 3, wherein a material of the dummydetection window comprises fluoropolymer, polysiloxane, high densitypolyethylene, low density polyethylene, or polypropylene.
 5. The methodof manufacturing the polishing pad as claimed in claim 1, wherein amaterial of the dummy detection window is a decomposable or dissolvablematerial.
 6. The method of manufacturing the polishing pad as claimed inclaim 5, wherein a material of the dummy detection window comprisespolyvinyl alcohol, polylactic acid, polyglucose, cyclodextrin,polystyrene, or salt.
 7. The method of manufacturing the polishing padas claimed in claim 1, wherein the dummy detection window is opaque andcomprises black, red, blue, or other dark colors.
 8. The method ofmanufacturing the polishing pad as claimed in claim 1, wherein amaterial of the polishing layer comprises polyester, polyether,polyurethane, polycarbonate, polyacrylate, polybutadiene, epoxy resin,unsaturated polyester, or ethylene-vinyl acetate copolymer.
 9. Themethod of manufacturing the polishing pad as claimed in claim 1, whereina material of the detection window enables a light with a wavelengthranging from 600 nm to 700 nm to have a transmittance of at least 50%.10. The method of manufacturing the polishing pad as claimed in claim 1,wherein a material of the detection window enables a light with awavelength ranging from 400 nm to 700 nm to have a transmittance of atleast 50%.
 11. The method of manufacturing the polishing pad as claimedin claim 1, wherein the detection opening is a through opening or ablind opening.
 12. A method of manufacturing a polishing pad having adetection window, the method comprising: providing a mold, having aprotrusion structure; filling a polishing layer precursor into the moldand performing a solidifying process to form a polishing layer, whereinthe protrusion structure defines a detection opening in the polishinglayer; and filling a detection window precursor into the detectionopening and performing a solidifying process to form a detection window.13. The method of manufacturing the polishing pad as claimed in claim12, wherein the detection opening is a through opening or a blindopening.
 14. The method of manufacturing the polishing pad as claimed inclaim 12, wherein a material of the detection window enables a lightwith a wavelength ranging from 600 nm to 700 nm to have a transmittanceof at least 50%.
 15. The method of manufacturing the polishing pad asclaimed in claim 12, wherein a material of the detection window enablesa light with a wavelength ranging from 400 nm to 700 nm to have atransmittance of at least 50%.
 16. The method of manufacturing thepolishing pad as claimed in claim 12, wherein a material of thepolishing layer comprises polyester, polyether, polyurethane,polycarbonate, polyacrylate, polybutadiene, epoxy resin, unsaturatedpolyester, or ethylene-vinyl acetate copolymer.
 17. A method ofmanufacturing a polishing pad having a detection window, the methodcomprising: providing a polishing layer, having a detection openingpre-formed therein; disposing a detection window in the detectionopening, wherein a gap is between a peripheral surface of the detectionwindow and an inner side surface of the detection opening; and filling abuffer layer into the gap.
 18. The method of manufacturing the polishingpad as claimed in claim 17, wherein the method of pre-forming thedetection opening in the polishing layer comprises: pre-disposing adummy detection window in a mold; filling a polishing layer precursorinto the mold and performing a solidifying process to form a polishinglayer, wherein the dummy detection window and the polishing layer areseparable completely; and separating the dummy detection window and thepolishing layer to form the detection opening in the polishing layer.19. The method of manufacturing the polishing pad as claimed in claim18, wherein a surface energy difference between the dummy detectionwindow and the polishing layer is greater than 10 mN/m.
 20. The methodof manufacturing the polishing pad as claimed in claim 17, wherein amaterial of the polishing layer is a polar material and a material ofthe dummy detection window is a non-polar material or a weak polarmaterial.
 21. The method of manufacturing the polishing pad as claimedin claim 20, wherein a material of the dummy detection window comprisesfluoropolymer, polysiloxane, high density polyethylene, low densitypolyethylene, or polypropylene.
 22. The method of manufacturing thepolishing pad as claimed in claim 17, wherein a material of the dummydetection window is a decomposable or dissolvable material.
 23. Themethod of manufacturing the polishing pad as claimed in claim 22,wherein a material of the dummy detection window comprises polyvinylalcohol, polylactic acid, polyglucose, cyclodextrin, polystyrene, orsalt.
 24. The method of manufacturing the polishing pad as claimed inclaim 17, wherein the dummy detection window is opaque and comprisesblack, red, blue, or other dark colors.
 25. The method of manufacturingthe polishing pad as claimed in claim 17, wherein the method ofpre-forming the detection opening in the polishing layer comprises:providing a mold, having a protrusion structure; and filling a polishinglayer precursor into the mold and performing a solidifying process toform a polishing layer, wherein the protrusion structure defines thedetection opening in the polishing layer.
 26. The method ofmanufacturing the polishing pad as claimed in claim 17, wherein amaterial of the polishing layer comprises polyester, polyether,polyurethane, polycarbonate, polyacrylate, polybutadiene, epoxy resin,unsaturated polyester, or ethylene-vinyl acetate copolymer.
 27. Themethod of manufacturing the polishing pad as claimed in claim 17,wherein a material of the detection window enables a light with awavelength ranging from 600 nm to 700 nm to have a transmittance of atleast 50%.
 28. The method of manufacturing the polishing pad as claimedin claim 17, wherein a material of the detection window enables a lightwith a wavelength ranging from 400 nm to 700 nm to have a transmittanceof at least 50%.
 29. The method of manufacturing the polishing pad asclaimed in claim 17, wherein a material of the buffer layer enables alight with a wavelength ranging from 600 nm to 700 nm to have atransmittance of at least 50%.
 30. The method of manufacturing thepolishing pad as claimed in claim 17, wherein a material of thepolishing layer is an aromatic-rich material, a material of thedetection window is an aliphatic-rich material, and a material of thebuffer layer ranges therebetween.
 31. The method of manufacturing thepolishing pad as claimed in claim 17, wherein a material of the bufferlayer is an energy absorbing material.
 32. The method of manufacturingthe polishing pad as claimed in claim 17, wherein the detection openingis a through opening or a blind opening.
 33. A polishing pad having adetection window, comprising: a polishing layer, having a detectionopening; a detection window, disposed in the detection opening, whereina gap is between a peripheral surface of the detection window and aninner side surface of the detection opening; and a buffer layer, fillingthe gap.
 34. The polishing pad having the detection window as claimed inclaim 33, wherein a material of the polishing layer is an aromatic-richmaterial, a material of the detection window is an aliphatic-richmaterial, and a material of the buffer layer ranges therebetween. 35.The polishing pad having the detection window as claimed in claim 33,wherein a material of the detection window enables a light with awavelength ranging from 600 nm to 700 nm to have a transmittance of atleast 50%.
 36. The polishing pad having the detection window as claimedin claim 33, wherein a material of the detection window enables a lightwith a wavelength ranging from 400 nm to 700 nm to have a transmittanceof at least 50%.
 37. The polishing pad having the detection window asclaimed in claim 33, wherein a material of the buffer layer enables alight with a wavelength ranging from 600 nm to 700 nm to have atransmittance of at least 50%.
 38. The polishing pad having thedetection window as claimed in claim 33, wherein a material of thebuffer layer enables a light with a wavelength ranging from 600 nm to700 nm to have a transmittance of at least 50%.
 39. The polishing padhaving the detection window as claimed in claim 33, wherein a materialof the buffer layer is an energy absorbing material.
 40. The polishingpad having the detection window as claimed in claim 33, wherein amaterial of the polishing layer comprises polyester, polyether,polyurethane, polycarbonate, polyacrylate, polybutadiene, epoxy resin,unsaturated polyester, or ethylene-vinyl acetate copolymer.
 41. Apolishing pad having a detection window, comprising: a polishing layer;and a detection window, located in the polishing layer, wherein amaximum tensile strength of elastic deformation between the detectionwindow and the polishing layer is greater than 85 kgf/cm².
 42. Thepolishing pad having the detection window as claimed in claim 41,wherein the maximum tensile strength of elastic deformation ranges from90˜100 kgf/cm².
 43. The polishing pad having the detection window asclaimed in claim 41, wherein a material of the polishing layer comprisespolyester, polyether, polyurethane, polycarbonate, polyacrylate,polybutadiene, epoxy resin, unsaturated polyester, or ethylene-vinylacetate copolymer.
 44. The polishing pad having the detection window asclaimed in claim 41, wherein a material of the detection window enablesa light with a wavelength ranging from 600 nm to 700 nm to have atransmittance of at least 50%.
 45. The polishing pad having thedetection window as claimed in claim 41, wherein a material of thedetection window enables a light with a wavelength ranging from 400 nmto 700 nm to have a transmittance of at least 50%.
 46. The polishing padhaving the detection window as claimed in claim 41, further comprising abuffer layer sandwiched between the detection window and the polishinglayer.
 47. The polishing pad having the detection window as claimed inclaim 46, wherein a material of the buffer layer enables a light with awavelength ranging from 600 nm to 700 nm to have a transmittance of atleast 50%.
 48. The polishing pad having the detection window as claimedin claim 46, wherein a material of the polishing layer is anaromatic-rich material, a material of the detection window is analiphatic-rich material, and a material of the buffer layer rangestherebetween.
 49. The polishing pad having the detection window asclaimed in claim 46, wherein a material of the buffer layer is an energyabsorbing material.